Answer:
D). They often are rich and vibrant in color.
Step-by-step explanation:
Superfoods are characterized as food items that are supposed to confer remarkable health benefits and provides a very concentrated source of nutrition including protein, fats, and other nutritional necessities. The key detail regarding the 'most of the superfoods having rich and vibrant color' from the fourth paragraph justifies a characteristic that most superfoods have despite their nutritional value. Thus, option D is the correct answer.